Help with VB Arrays? 2

[JohnZ]

Hello,

I'm taking a course in Visual Basic and I'm having lots of trouble, especially using arrays. For example, our assignment reads: Write a program that displays the nine different units of measure, request the unit to convert from, the unit to convert to, and the quantity to be converted, and then displays the converted quantity.

1 inch = .0833 foot 1 rod = 16.5 feet
1 yard = 3 feet 1 furlong = 660 feet
1 meter = 3.2815 feet 1 kilometer = 3281.5 feet
1 fathom = 6 feet 1 mile = 5280 feet

Is there anyone that can help me? Or does anyone know of another site that can help me? The book I'm using is Visual Basic 6.0, 4th edition, by David I. Schneider.
Thanks

 

[jimgao]

you want to use array in this case? can you use select case ?

 

[MichaelRed]

Public Function basConvertUnits(MyVal As Double, FrmUnit As String, ToUnit As String) As Double

    Sample Usage:
    'frm$ = "Yd"
    'ToUnt$ = "Mile"
 
    'Print basConvertUnits(1#, "Mile", "Kilometer")
    ' 1.60902026512266

    'Print basConvertUnits(1#, "Inches", "Kilometer")
    '0

    'Print basConvertUnits(1#, "In", "Kilometer")
    ' 2.53847331766782E-05

    'Print basConvertUnits(17#, frm$, ToUnt$)
    ' 9.65909090909091E-03


    'I 'm taking a course in Visual Basic and I'm having lots of
    'trouble, especially using arrays.  For example, our assignment reads:
    'Write a program that displays the nine different units of measure,
    'request the unit to convert from, the unit to convert to,
    'and the quantity to be converted, and then displays the converted quantity.

    '1 inch = .0833 foot
    '1 rod = 16.5 feet
    '1 yard = 3 feet
    '1 furlong = 660 feet
    '1 meter = 3.2815 feet
    '1 kilometer = 3281.5 feet
    '1 fathom = 6 feet
    '1 mile = 5280 feet

    'This is done ONLY to illustate the use of the ARRAYS.
    'In any REAL world Process, this would be woefully inadequate.
    'You would need to chaek that the from/to Units were both Included and Compatible.
    'A "Real" system would include maany different Types of units (Area, Volume, Energy,
    'Time, Weight, Mass, Velocity ...).  With the myraid of conversions to consider,
    'simple arrays used in this example quickly become to complex to be reasonable and
    'would generally be replaced by a database/table.  Even in this example, You need to
    'make sure that the Units are entered correctly, and that SOME value is provided
    'for the conversion.  Here, we only check that
    'both a From and To conversion Units were 'found'.  The ONLY indication of a problem
    'is the return value (If it is Zero, you can assume ther is a problem!)
    'The 'Program" checks that a numeric value is supplied for the Value argument
    'and will generate an error if no value is input.


    Dim Conv(10) As Single
    Dim FromTo(10) As String
    Dim Idx As Integer
    Dim FrmIdx As Integer
    Dim ToIdx As Integer

    Conv(1) = 0.0833        'Ft/In
    Conv(2) = 3#            'Ft/Yd
    Conv(3) = 6#            'Ft/Fathom
    Conv(4) = 16.5          'Ft/Rod
    Conv(5) = 660#          'Ft/Furlong
    Conv(6) = 3281.5        'Ft/Killometer
    Conv(7) = 5280#         'Ft/Mile

    FromTo(1) = "In"
    FromTo(2) = "Yd"
    FromTo(3) = "Fathom"
    FromTo(4) = "Rod"
    FromTo(5) = "Furlong"
    FromTo(6) = "Kilometer"
    FromTo(7) = "Mile"

    'Generic Algorythim for this (simplistic) Example:
    '[MyVal] * Conv(From) / Conv(To)

    'But, of Course, You need to Relate From & To to valid indicies of Conv
    For Idx = 0 To UBound(Conv)             'Loop through (valid) Conversions

        If (Conv(Idx) = 0) Then             'Check a Conversion Value Exists
            GoTo NoConv                     'Don't look For Conv Index if No Value
        End If

        If (FrmUnit = FromTo(Idx)) Then     'Look Up the From Index
            FrmIdx = Idx
        End If

        If (ToUnit = FromTo(Idx)) Then      'Then the To Index
            ToIdx = Idx
        End If

NoConv:

    Next Idx

    If (FrmIdx * ToIdx <> 0) Then
        basConvertUnits = MyVal * Conv(FrmIdx) / Conv(ToIdx)
     Else
        basConvertUnits = 0
    End If

End Function

MichaelRed
mred@duvallgroup.com
There is never time to do it right but there is always time to do it over

 

[dsi]

You could also set up constants:

Public Const FTtoIN = 12
Public Const INtoFT = 0.0833
.
.
.

inValue = ftValue * FTtoIN

ftValue = inValue * INtoFT

DimensionalSolutions@Core.com